diff --git a/gtk/resources/theme/Adwaita/_common.scss b/gtk/resources/theme/Adwaita/_common.scss
index ee1440749e..f24c77c5b4 100644
--- a/gtk/resources/theme/Adwaita/_common.scss
+++ b/gtk/resources/theme/Adwaita/_common.scss
@@ -131,6 +131,11 @@
 }
 
 GtkLabel {
+  &.separator {
+    color: $fg_color;
+    @extend .dim-label;
+    &:backdrop { color: $backdrop_fg_color; }
+  }
   &:selected,
   &:selected:focus,
   &:selected:hover {
diff --git a/gtk/resources/theme/Adwaita/gtk-contained-dark.css b/gtk/resources/theme/Adwaita/gtk-contained-dark.css
index 5bda289e04..19e1ea3457 100644
--- a/gtk/resources/theme/Adwaita/gtk-contained-dark.css
+++ b/gtk/resources/theme/Adwaita/gtk-contained-dark.css
@@ -83,12 +83,19 @@
 .overshoot {
   background-color: rgba(33, 93, 156, 0.2); }
 
+GtkLabel.separator, .sidebar GtkLabel.separator:backdrop,
+.sidebar .view GtkLabel.separator:backdrop {
+  color: #eeeeec; }
+  GtkLabel.separator:backdrop, .sidebar GtkLabel.separator:backdrop,
+  .sidebar .view GtkLabel.separator:backdrop {
+    color: #c9cbc9; }
 GtkLabel:insensitive {
   color: #939695; }
   GtkLabel:insensitive:backdrop {
     color: #5d6767; }
 
-.dim-label, .titlebar .subtitle, GtkCalendar.header .subtitle,
+.dim-label, GtkLabel.separator, .sidebar GtkLabel.separator:backdrop,
+.sidebar .view GtkLabel.separator:backdrop, .titlebar .subtitle, GtkCalendar.header .subtitle,
 .header-bar .subtitle {
   opacity: 0.55;
   text-shadow: none; }
diff --git a/gtk/resources/theme/Adwaita/gtk-contained.css b/gtk/resources/theme/Adwaita/gtk-contained.css
index 223bd64f42..03c12c2fa8 100644
--- a/gtk/resources/theme/Adwaita/gtk-contained.css
+++ b/gtk/resources/theme/Adwaita/gtk-contained.css
@@ -83,12 +83,19 @@
 .overshoot {
   background-color: rgba(74, 144, 217, 0.2); }
 
+GtkLabel.separator, .sidebar GtkLabel.separator:backdrop,
+.sidebar .view GtkLabel.separator:backdrop {
+  color: #2e3436; }
+  GtkLabel.separator:backdrop, .sidebar GtkLabel.separator:backdrop,
+  .sidebar .view GtkLabel.separator:backdrop {
+    color: #54595a; }
 GtkLabel:insensitive {
   color: #8d9091; }
   GtkLabel:insensitive:backdrop {
     color: #c7c7c7; }
 
-.dim-label, .titlebar .subtitle, GtkCalendar.header .subtitle,
+.dim-label, GtkLabel.separator, .sidebar GtkLabel.separator:backdrop,
+.sidebar .view GtkLabel.separator:backdrop, .titlebar .subtitle, GtkCalendar.header .subtitle,
 .header-bar .subtitle {
   opacity: 0.55;
   text-shadow: none; }